1. From the Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Virginia Medical Center, Charlottesville, Va.; the Department of Pathology, St. Michael's Hospital, University of Toronto, Toronto, Ontario; and the Peptide Biology Laboratory, Salk Institute for Biological Studies, La Jolla, Calif. Address reprint requests to Dr. Carey at Box 482, University of Virginia Medical Center. Charlottesville, VA 22908.